Field of the Invention
The present invention relates to a system for determining credibility of given information and, more specifically, to a technique for determining credibility of information based on remarks of many users on the Internet and on knowledge of causal relations.
Description of the Background Art
Search engines and question-answering systems offered on the Internet have made it possible to efficiently obtain necessary information from huge amount of texts on the Internet. A large amount of information thus obtained, however, may include pieces of information of questionable credibility. It is extremely difficult to verify each of such pieces of information. By way of example, consider a system that offers disaster-related information through question-answering. When a question “What is occurring in Cleveland” is input to this system, a possible answer candidate may be “Rivers are flooding.” We do not know, however, if this answer is credible or not.
Estimating credibility of information output from search engines and question-answering systems has been an enormous technical challenge from the early stage of search engines. Typical technique is disclosed in Non-Patent Literature 1 (KUROHASHI et al., “Joho-bunseki system WISDOM—Web no kenzen na rikatsuyou wo mezashite—(Information Analysis System WISDOM—to attain healthy use of Web—), Mar. 31, 2011, National Institute of Information and Communications Technology, Knowledge Processing Group, Information Credibility Project, retrieved on the Internet on Feb. 1, 2016, which considers attributes of an information sender. This approach has a problem that accurate attributes of information senders can be obtained only in very limited situations. Because of this problem, the application of this technique to texts on the Internet has attained very limited effects. Another approach presents very rough attributes of an information sender such as domain information of a site from which the information is issued, and leaves the user to determine its credibility.
Another technique for determining credibility of information is disclosed in Non-Patent Literature 2 (MURAKAMI et al., “Generating Statement Maps for Capturing Supportive and Contrastive Relations between Statements”, Information Processing Society of Japan, IPSJ SIG Technical Reports, 2008-NL-186, pp. 55-60, July 2008). This is a technique referred to as “statement maps” (statement maps generating problem). In the statement maps generating problem, for an input piece of information, a piece of similar information and a piece of contradicting information as well as pieces of information as supporting grounds are displayed in a distinguished manner. Then, a human determines, based on the statement maps, whether the input piece of information is credible or not.
A technique similar to the statement maps generating problem is described in Non-Patent Literature 3 (Rob Ennals and Beth Trushkowsky and John Mark Agosta, “Highlighting disputed claims on the web,” Proceedings of WWW2010. pp. 341-350, 2010), which is called Dispute Finder. Dispute Finder is provided as an extension of web browsers and has a function of highlighting passages in a web page which the user currently reads if the passage is controversial on the web.